In the manufacture of integrated circuits it has become common to employ anti-reflection coating (ARC) techniques to improve the control of critical dimension (CD) tolerances. Typically a layer of ARC material is formed between a substrate and a layer of photoresist. The layer of ARC material is a dielectric material that eliminates reflections of incident light from the surface of the substrate from affecting the critical dimension of patterned photoresist lines.
The ARC technique utilizes (1) a phase shift cancellation of the reflections from the interface between the bottom of the photoresist layer and the top of the layer of ARC material, and (2) a phase shift cancellation of the reflections from the interface between the bottom layer of ARC material and the top surface of the substrate. The layer of ARC material is designed so that its optical properties and thickness (1) create a phase shift equal to one half of a wavelength of the incident light, and (2) cause the reflections to be equal in intensity so that the cancellation of the reflections will occur.
Prior art anti-reflecting coating (ARC) material is typically made from silicon oxy-nitride (SiOxNy) material. The prior art ARC material must be removed after the photolithography procedures are completed. This is because the presence of the ARC material would impede the formation of cobalt silicide in subsequent processing steps.
It would be advantageous in integrated circuit manufacturing to have a material that has anti-reflecting coating (ARC) properties that does not need to be removed before subsequent processing steps are performed. It would also be advantageous to have a material for a hard mask for a silicon etch process that does not have to be removed before subsequent processing steps are performed.
Before undertaking the Detailed Description of the Invention below, it may be advantageous to set forth definitions of certain words and phrases used throughout this patent document: the terms “include” and “comprise,” as well as derivatives thereof, mean inclusion without limitation; the term “or,” is inclusive, meaning and/or; the phrases “associated with” and “associated therewith,” as well as derivatives thereof, may mean to include, be included within, interconnect with, contain, be contained within, connect to or with, couple to or with, be communicable with, cooperate with, interleave, juxtapose, be proximate to, be bound to or with, have, have a property of, or the like. Definitions for certain words and phrases are provided throughout this patent document, those of ordinary skill in the art should understand that in many, if not most instances, such definitions apply to prior uses, as well as future uses, of such defined words and phrases.